It’s 8.30am in Santa Monica, California, and David Seidler, Academy Award winning author of The King’s Speech, has a tall cappuccino by the side of the phone and no doubt a view of the sunlit sea. On my end of the phone, in Guildford, it’s 4.30pm and a rainy teatime.

LA and David feel very far away but the writer of last year’s most lauded film is about to be connected with Guildford forever: in a major theatrical coup, the town’s Yvonne Arnaud Theatre has been chosen for the world premiere of the stage version of The King’s Speech.

In February Seidler will be in the audience when Charles Edwards steps on to the Arnaud stage as King George VI, the reluctant King who has to step in to the limelight when his older brother abdicates, with Jonathan Hyde as the Australian speech therapist Lionel Logue who helps the King control his stammer so that he is able to make rousing wartime speeches.

First we settle the question of whether The King’s Speech was originally conceived as a play or as a film.

It has often been reported that it started out as a play and was turned into a screenplay, but Seidler confirms he wrote it first as a film.

“I was 70 pages into the screenplay and I wasn’t sure what I had there so I showed it to my then wife and she said ‘It’s lovely but it’s not focused enough so why don’t you take a crack at writing it as a stage play, forcing you to focus on the key relationships.’

“It was good advice so I threw away the 70 pages and sat down and wrote a play and it took off lighter than dough. Then I showed it to the producers and of course they said ‘Wouldn’t it make a good film?’ So it was rewritten again as a film.”

Though screenwriters normally remain in obscurity, while the film’s director and actors garner attention, the way Seidler’s personal story is echoed in the film has thrust him into the limelight. Famously he suffered from the same affliction as King George VI.

How did it feel as a young person to have a stammer? “Bloody miserable.” says Seidler affably.

“It colours every moment of the day. You are worrying ‘Is the teacher going to call on me to speak? What will I do when it’s my turn to tell a joke?’ A 15 minute joke doesn’t work.”

Seidler lost his stammer in what he calls “the manner that got us an R rating for the film in the US”. He means that, like the King in the film, he got angry and swore.

“I was 16 and had been told that if my stutter was not under control by then it might never be. I got very upset.

“I couldn’t ask girls out. I found myself jumping up and down on my bed in rage saying the f word. It was unfair, I was not a terrible person so why had the gods given me this affliction?

“Once I made that psychological leap that I had an entitlement, that I deserved to be heard no matter how my voice came out, within weeks the stammer had gone.

“I auditioned for a school production a while later and played a Christian eaten by a lion – well, I can tell you I didn’t stutter as I died.”

It was painful but cathartic for him to revisit the old demons when he wrote the screenplay. “It’s like having a toothache – you can think only about how you want the pain to stop but once the dentist drills and the pain goes away you don’t want to think about it anymore.

“So once my stammer went it was the last thing I wanted to think about.

“But then I got into doing the film and worked with Colin Firth – who asked some very probing and intelligent questions about how it felt physically and psychologically – so I had to go into it again. Ultimately it was cathartic.”

When The King’s Speech finally made it to the cinema it was the culmination of a long wait for Seidler.

He conceived the idea for it back in the early 1980s and had conducted his research, including talking to Valentine Logue, the son of Lionel.

Logue was prepared to give Seidler access to transcripts of his father’s sessions with the King but wanted him to get permission from the Queen Mother before he went ahead.

The Queen Mother’s secretary wrote back to Seidler and asked him politely not to do it in her lifetime.

“I was incredibly disappointed but on other hand when the Queen Mother makes a request like that, as someone who was born British and still feels it to a large extent, it would have been churlish to disregard her.

“Actually she did me a favour. I could have written the play originally 30 years ago but it wouldn’t be quite what it has turned out to be. It needed those years of maturity.”

A lot of work has gone into converting the screenplay into a play, says Seidler. “It’s been streamlined. The cast was too large to be practical for a play.

“There are nine characters now and I’ve honed the dialogue. There are some great new twists. For instance, in the play the Archbishop of Canterbury and Churchill act almost like a comic Greek chorus exchanging mischievous remarks but in the movie they don’t have a scene together.

“It works wonderfully on stage but (director) Tom Hooper felt it wrong for the movie and I think he was right.”

There were many good reasons to open the play in Guildford, Seidler explains. “It would be an act of hubris for us to go straight to London or New York.

“It’s up to the critics and the public whether there is enough interest. Guildford’s proximity to London makes it easy for the actors and it’s a marvellous theatre which suits a history play that moves rapidly from scene to scene.

“We also felt the audience in Guildford would be perfect and respond to the material well.”

He feels just as excited about the play as he was about the film and believes it will reach new audiences as well as those who loved the film.

“It’s a completely different experience with live actors – and I’m thrilled with the calibre of the cast and with director Adrian Noble. I really love theatre and have wanted to be part of it since I was a little boy.

“Coming back to austerity England from the US after the war, my grandfather would take me to plays at the Hippodrome at Golders Green to see creaky old British plays with all the great old stars coming out.

“The leading man would sweep on to the stage in a pool of light. It was wonderful and I dreamt one day I would be part of it. The dream has come true and that little boy will be sitting in the audience on the opening night at Guildford, still in awe.”

The world premiere of The King’s Speech opens at the Yvonne Arnaud Theatre on Thursday February 2, 2012 . The play runs until Saturday February 11. For tickets call the box office on 01483 440000 or visit www.yvonne-arnaud.co.uk